Polishing Aluminum to Mirror Finish: Sanding Guide (400–3000 Grit)

Aluminum is lightweight and durable, but it scratches and oxidizes easily. Sanding and polishing can restore dull aluminum surfaces to a brilliant, mirror-like shine. This guide explains the correct grit sequence and techniques for polishing aluminum.

Why Sand Aluminum?

Sanding removes oxidation, scratches, and surface imperfections. It creates a smooth foundation that allows polishing compounds to bring out maximum shine. Without sanding, oxidation and scratches remain visible even after polishing.

Best Tools for Aluminum Polishing

• 9x11 in silicon carbide wet/dry sandpaper sheets
• Soft sanding block or orbital sander
• Spray bottle with water
• Microfiber towels
• Aluminum polishing compound and buffing pad

Recommended Grit Sequence

• 400 grit: Remove heavy oxidation or scratches.
• 800 grit: Smooth sanding marks.
• 1200 grit: Refine clarity.
• 2000 grit: Pre-polish surface.
• 3000 grit: Final wet sanding before buffing.

Step-by-Step: Sanding Aluminum

1. Clean the surface. Wash aluminum thoroughly to remove dirt and grease.
2. Start with 400 grit. Wet sand to cut through oxidation. Use 400 Grit (25-pack).
3. Move to 800 grit. Smooth coarse scratches. Try 800 Grit (50-pack).
4. Refine with 1200 grit. Create a satin surface. Stock up on 1200 Grit (100-pack).
5. Polish with 2000 grit. Prepare aluminum for high gloss.
6. Finish with 3000 grit. Lightly wet sand for a mirror-ready surface.
7. Buff and polish. Apply aluminum polishing compound with a buffing pad until it shines.

Special Cases

For deep gouges, start with 220 grit before progressing. For thin aluminum sheets, avoid aggressive sanding that can warp the material.

Pro Tips

• Always wet sand to reduce clogging and scratches.
• Sand in alternating directions with each grit for uniform results.
• Use microfiber towels to avoid swirl marks during polishing.
• Seal polished aluminum with wax to slow oxidation.

Aftercare

• Clean polished aluminum with mild soap and water only.
• Reapply polish periodically to maintain shine.
• Store sandpaper flat in a dry location.

FAQs

• Can I polish aluminum without sanding? No—sanding is required to remove oxidation and scratches first.
• Will sanding damage aluminum? Not if you follow proper grit progression and use light pressure.
• Do I need to clear coat polished aluminum? Optional—clear coat protects but can reduce maximum shine.

Watch & Learn

For mirror-like aluminum finishes, explore our full range of wet/dry sheets in the Super Fine Sandpaper Collection.